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Specific resistance of a conductor increases with :
A
Increase in temperature
B
Increase in cross section area
C
Increase in cross section and decrease in length
D
Decrease in cross section area
Detailed Solution
Specific resistance (resistivity) $\rho$ is a property of the material. It does not depend on the geometry (length or area) of the conductor.
For a metallic conductor, resistivity increases with temperature: $\rho_T = \rho_0(1 + \alpha\Delta T)$, because the ions vibrate more and electrons collide more often.
Changing length or area changes the resistance $R = \dfrac{\rho l}{A}$, but not $\rho$.
So the specific resistance of a conductor increases with increase in temperature.
For a metallic conductor, resistivity increases with temperature: $\rho_T = \rho_0(1 + \alpha\Delta T)$, because the ions vibrate more and electrons collide more often.
Changing length or area changes the resistance $R = \dfrac{\rho l}{A}$, but not $\rho$.
So the specific resistance of a conductor increases with increase in temperature.